SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83f1c96d33b3b3cca2324f010eeccc434cdd0fcdf8e9e963131ff1f8cfb22aaa' 
  AND token = '243ZjP8m5FOIrtJwsWdo0x3xZ6W4llhurLZRv5Q8l0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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