SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40fa892056bc62e88bc94676b4a27d371bfa15b26fbbf6df74943828c6a1f03c' 
  AND token = 'avYBlF2KNoxuHSWkLYxskIr05EV9qivXk22JsxMVTPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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