SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fd411097dabaaf230cff85bddb80a309e65e1830beebb53d4a09b806eb3161b' 
  AND token = '3SnvI3UbdPilZbOAajwrMgliD+7ynhndnvAPV8HE8vA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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