SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4f72a7202d9788ed9edba05e5986a52ce0556d60640749ee51ad34b72588604' 
  AND token = 'HBT9niThy+Qce5iKnVkOj+6pEfziJlGaXrKSOjD5JXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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