SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff23e4283b3e82a8ad6780e513364d99357a168692963e44decd896a41958d2c' 
  AND token = 'WAlMcvVFV7OrNF6SitECMjsVtsQwpPQ4frmfrKaQWnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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