SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ffa113cb4a763a56a6f102b96cb04b6c8d0ba4c8e31d30800ba3ef4fd12803c' 
  AND token = 'KuR94+8RTfAf29o/JluNwie2YOLfm8DePgeaKE8BJfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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