SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd46c8bde81ecf42b6dbb29b549b7140186d457e8c10f0b9685721e1bb81aa707' 
  AND token = 'HwqtxhWGmLG7+2Jtnrs+azOZ0+bUCqsrlduOxVwuFp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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