SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '148a86fc21cc6cbed3ac26ab876c9267b47dae91ef88614b3b0515731bc448b8' 
  AND token = 'eHuPGojpzMlkVRpT9mmPTvkwUCHUqKlvQwRI+qkN8tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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