SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6938b43df9cc48c403bb6c52d02ae7ebdaa1a4a83a054e6bcc662fe976b75758' 
  AND token = 'pHG9vf6V22HzdBg3pRqDxqbkpI/iFzimDl+k5Qr7jwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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