SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '69d556bb1694c27208663cc41e1c7ae60656d8003e7328cf0a0b43df1b5d5442' 
  AND token = 'kL81ffm2Laq1CfneUDKfv0Pvu+mfNlcTrlKhowYGUZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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