SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'db934b3d449a09d66c79349a98ffbaddf33cbfaf6afc2fd99a6176baa3c4e54b' 
  AND token = 'PgeC+hVxcZ2fTDY13E/ccgETe4NCahUzEI7zwFtaRJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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