SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b71ba67587418e10320c0f74e8eee2d7ef3fe9860a469600447bbf044088c0de' 
  AND token = 'TzVnHuDyAsl3reUQRCIbWCmpZiXFQvcU2bDwv3zrohs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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