SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f10b4016323ad0ccc7926574e8f9307c2a3f54e7a7bc1a49a5706d96cf271b4f' 
  AND token = 'kLbIByyiz97sJlshZI4WjzWvJ1P90o+KICmnmSw8Kq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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