SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de445d43321069818f885bc7eb9583251c925b81d786e2f9f92049eca923b510' 
  AND token = 'VhRxW+w35W/uNAoVK7y+bexER+RgxhyNsmalLE0DL98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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