SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ccd2463bbe670c2a15bfaaaf56823651530ff40ff4bdc1b75b2f2b7a87ccca0' 
  AND token = '/U3Y4yILSdqJoJJ3lhN9nbwfOGX6/XhWTBxKZCPHtZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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