SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f8492168991bcdd11a54e8ae2e8aa7a1baa3921eeea0d34e399e1343eb8c3fd' 
  AND token = 'jqplDKCApdneSxzrnfXqPBs+e9ipMYo1y14ia3loCIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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