SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4dc4e85a53815069b4b4f6fa225c3d7db5785da09cff2c1266e69e27b34fdfe7' 
  AND token = '9WiOt5SFties0EU4q7iETCv7sMJwaudGDl9UeyJ/j4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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