SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6716c57d4bc8eecff2aec2b9364b38100f8e054d689d05985aa4d7af9b521db' 
  AND token = '9K/5YelSpUhO9d0GYU3SMHlL1KFjQbbBL7hw6+ud578=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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