SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef235072ce14a99170ef24617b52aa31278858ad8ada5ef8385de613ac09dc8a' 
  AND token = 'lwVo6FQB3xjtPXFmPmMrtZKcdnS1wp7Kg6qVzF9oTZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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