SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bb10dae7bbb2548e079bdd5367f62fd434134f6f65e6ae460050ea0aced1364e' 
  AND token = 'NzuhErPGRulL750J1O2WlBX2F7barTVXK84kT5srLqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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