SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4afef6c90af09f6160f209e847ed4cdc5b4cfbfe3f090c331253549f86067ab1' 
  AND token = 'CWkzT6cs56FD8KdfHzcZcJc0b7ux+dTKe/5CYSAfWRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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