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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efe498b291de2ba7802b3dd421a12eca0ff81d6feb9f29ddcb4454c0a5b22e5c' 
  AND token = 'fg0/P4z5iCD6r1AiqBaBTI2/LM58OOzSUxcAGq8KtPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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