SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '08ea5c237a8db807de979769603da4350a1569bc8e7a3666e1c5baf4991d52b7' 
  AND token = 'FVi0BmH8YBkjj0NSDAgSlj3XV1nzLHtIBs3TBr1a3I4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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