SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e37d7ffaca2271a9bdc61345348407206b3b8cf197e9abecef98ff96ad7a4aa' 
  AND token = 'wmJIKgGvEe+E8W3v9kF8s6ZmNsTj8B4CMaljmiG3D/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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