SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a60fb509db4b498c5b150fc4c638903251910717b90be583f948b5bbaa40373e' 
  AND token = 'mvzyntX+CTF5RgtlBGm9gOD5iq+jpK4B4gDc9p6Y+So=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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