SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1574e3e71b10c5a5736316a67de8096066fba44adc1a675590b919857d9a74c5' 
  AND token = 'qTZHup/Nji+aYvdehpFRkuyVfMoxpLqu5O4jbG9wRKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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