SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ecac2e66ca3887719c55e9b274dbdae65e11bb289bdf87be93c3481b9192fb0' 
  AND token = 'dKC8bEnCbKRfrDBaSI7EbIw35Q438msJALYHjUjov4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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