SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c76d3227de992a7ac22311296273a2800b4ce37f6a06eba526fc39feafe73dcc' 
  AND token = 'zashdSbIH4ZBVmQ2BOAZT/uI6Jqon13uiOtgaUZMUu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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