SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a98f301092a4412e15a6de15582cddbdb7dc496a5eddb1a0ea336040945cb91' 
  AND token = '77pEZH4+wSKMS9Jkh63iJSo2Pb79NdQ28U8cXDkvejw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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