SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '284ae834113effafdbe997ec00ab874d6bb0dea94e91e77fc67f6df23ddeddc6' 
  AND token = '4p+tHJvvw5Z64z2jhOtMAYmWN5W8sAGhfgEbND0VCug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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