SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9f1445968597a23f772c1060f165f749190a391c87d4e4c4c30915e41bfaf88' 
  AND token = '3ONzndmGgkuwupZhAiQ4v+3+YOHhMeziOwA5k+xyQwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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