SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c9e0f016eb08d1a38f266e261fcb849f2327ceb3fef5a774a4fbcc28d93466e' 
  AND token = 'U1Q+wGyVYNE27bUHrYbOPO0XWEE8u9c7IBJELiifgac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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