SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e8a53350c503712dbbcca894677573b4aa3961abcb3efc1eb5f5948d023310bc' 
  AND token = 'Ts4kFDZ8hSp+S6mV2epzPhfnl4z8eMnnxqkHqRwcT18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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