SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '103356581983729ac40001acec8f30b47675bcf5720e9812bb4410012fd74298' 
  AND token = '+VNWWLMBFHO1eDnu2+OYnIMPJpZxxIDgPvblvvadHc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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