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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '20a192ef22140db0f8a18e83bf2cad76e4ae4d47af713ee7f7b20c4d47046903' 
  AND token = 'SUf0WqeqeT/Qi5ydA1mGGGbjHPwWo3MD+OTIWZrnjkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}