SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9644475880736233bc31d6bf869c83540299be8d9c0464bb45f4b1407746e7df' 
  AND token = 'yEZ/YLGEYbAQIvYKQA3bODPGHRTuVPbMY2oULH9tSxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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