SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e9bdf657934642e2b16ca965071c1545b10e435367e3643fd5ee660b199f212c' 
  AND token = 'RMKK1j0oTzas3G3fU6nJmxSp03Ajw92h23DUocy5T6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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