SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f388b24b95d0b3bd0e74d35de120ff23398053ed7f4a68784d541c39d6aece08' 
  AND token = 'D2TjbS/gVcS0jKbIYO5/BYhOJX+Rev0crZoWamZlfXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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