SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eab8d931942f750b08692b7648e66a1777d5524ff2020a7e899b0028c23a06f' 
  AND token = 'XQJVbiP1QlLgH6VnOsKLlPWawFWqlXVaTt0o7mZpGJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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