SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a31ff1c916a9f3697915b5663a4128a587ba0492773682ba15d79e77013ce57' 
  AND token = 'Zf8NyzIYp+Z1tW8Z4eCb+uJ1dlWsZPAOumC7rqUfZf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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