SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40c3824db98b2298753de62020051c433303de83623d0c1cbbcc2fbe758192f1' 
  AND token = 'xOH5g9gteAauNVUufsBwuuDdaczLVqF2CZ+dkFiGulY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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