SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e2bfc385c422b4e0af2771f4d02aea17de44dc004f839153601c55671e28bb9' 
  AND token = 'CaGK9REAn/GqKIvArhHXymZqdUTBkxToIrM+sKqXNTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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