SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f681974812ba39ad6bab5b98e2f5a7a95a6bab41a3a25ec5cbab9b379491b6c4' 
  AND token = 'N6jjLpu8PbEjqMbYt18qKw3pLIXjKD9th+7Y2ol5+fU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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