SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8336a3dd84955e3c52a3525f871752dc26520992142a44e3f5342291bb7b0092' 
  AND token = 'hXTEMj8qRaoIzRQuM+tazuTk+mFxuwkBw36061Eb8Gk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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