SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa1676c14edd2ca6440a2aa13dcee2aeea4479e00ae110716130f1f57b816085' 
  AND token = 'nIRBbV0jfCOuUoPyaDsm7keSOGz6EVeUsl27fM4whWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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