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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '718f6e8e929a9a38edab3deb9c45d3d29bdc5a9a7ae6b2553ae3ccefaaf616a8' 
  AND token = 'jzLENeGTDgv7Ke/ErFP7Ms4z/J31Hzh3gSJH/ZiNUTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}