SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14a3435a94999c437348ecd0ea6c403cc297f431cbb147aca5c9ddd7cfa9611a' 
  AND token = 'j5f9MTMbZtMgozNtv/von6EPUA5Dp7Wm4WBo8eIEqYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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