SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13ad9823d171a7c8875e178107c8337f6b9b3f968af948a488a9d99158c41aff' 
  AND token = 'QSf91wV11ASNn1XafgU0GjkVka1VnpGyOEs+VQP+w8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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