SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd358fd158b157e132928d4bdb7ec220ca0a89213975286c8e5a5ca4360e42785' 
  AND token = 'KQxlDYF0NOnCNyD4IS37pflbDuRaX34dFc/m1BpbYLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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