SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa51d83301dea6af7488f53958db5717ab0a6214509b42ab7bd2921e6e480118' 
  AND token = 'E834wPvz0STMLj+qUKTJZsCnjf2EnHlacmEKxVryfQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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