SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4e605d56621bb329d8e524799adf02bdb8d159b003e8a3d59049026b2befeae3' 
  AND token = 'ierj52J01/OdLPZXiTWoi0Kg6dA0XRRwsgaSAJg/rVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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