SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53fe88470dc40723abf9d8827f0e875b7406b79eed1e3499fe5f0167c00a5849' 
  AND token = 'nd5Y/hvOd/QlTjRU6Wa9DGdwhkhmeVWr5MZ+Bv12Y3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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