SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5862b12ad73c2af7df92fbef854a07c8db0a8b9c2a110ec9f52708edac190401' 
  AND token = 'yyKLH2gtuv1vQfFZ2wl0OlvmIxKGnVDm4hoJnp/3L+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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