SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73b5ab33ae8c203f66001f16501546cb3e245003c5e7ab31fb6c35faad97fc5d' 
  AND token = '6WmyTm0BMdcPSJpZRt2dEer8M0i7MasHcH98EFlPSDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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