SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '850d1d7aed9192a8ffe4884d9aaa9f607ae0c6162481068821014bf42627bf26' 
  AND token = 'nvKI4Xm2oqV+pvF+XB/kI+ADnc7zJ7zyyDfT493xhFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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