SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bc529d233e28d76a3cb3cb1c3b7bcae2144a291b5960bf498046e2c3e1abda84' 
  AND token = '21hlW2g7qUNmg0PGRslTKPgHT9f4wfw7AtkJ5+ilfzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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