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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb4423381252b6a48dcf1a4fab1505115f8b1178332a34e9bbd84e24e4f3d20e' 
  AND token = 'PCaXqSg7pKqDalPNMeLIPxHeCQG/cQttENCu8zbSGOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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