SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0c383b3dea3a993c73f3bdbc9302499473eb2fd9001f485b8bf2b052c01862d7' 
  AND token = 'YLHHrY79fFluKb4z+vNobp8DWbaAKQkKfCPEQ0zf0To=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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