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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9a3207cb592483c02c6d5c8cb11f41a73b3b6e008da7b7cea3dbd4d32c45261' 
  AND token = 'lgNffbo3WobCcETv1fnLuYYsY1TimCsN55AQckj/yqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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