SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd281d6143f417ca43e1d7d99cd318aa2cfa0778c426ef1b33f015fdee22bfe94' 
  AND token = 'JZgx+hhqe9YHWA09YsjYGchucCU9BGIK15Y6VY/boyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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