SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18901211383ae4709dddba1ca7f98bd61661522a2c9da3426fa57cc395822aca' 
  AND token = 'EaKO6r+SJyHLeOcWKiWVJwcI4r5sn12feG95nAlAB3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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