SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '548578de6b64a9135eb0b1a7c51b1ad816d13bf6919050395901874d4d66b952' 
  AND token = 'kFBjwh4t4/zgOT7SNxx+poVyX4/HqoMNJolxR80RpAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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