SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '671d84031775cbc3241b53a60f100fc85658c97ced3ab45ebed20eda79ef3d36' 
  AND token = 'g+/Kevz9H/F1zs4vL/M0Rvzy30hI42WPK9XAqS/45rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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