SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '755906c2086e96364eb037606f910523d8fdf885f52ff20de53171c1ddeb1eff' 
  AND token = 'KqytsjR/TNY1OaclWthx8MD8sMK5NtvifLG5d9pxIyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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