SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd36f065e15b5cf35b5282011e9a2b35c9e54f484a50c1de15e43c918e68f86d2' 
  AND token = 'n9p+uUEN/gNwFNjfsiMBqEmkx0PzZHOkuakOONXXFe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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