SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3eb3cac7b690190998e038060b9eeab0549d7c4b300f81b3ed94ee3a46960d0b' 
  AND token = 'nB7lX7oMql9+tSlUnjBHq8XeL8oqUFp8CDyEFWjwMyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00638

JSON explain

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