SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25cd473dbcff869c9773aa7b8baca1d35f6d8ed734b0a09453014febd87b7935' 
  AND token = 'v+nKw4CrdyhWOxM3lLXD3zj2OCtUbAUrG6YRr0maP/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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