SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d374b561e173178d34706184c4b4904d86424d43035dec766196ec5dbdea0de' 
  AND token = 'rXNZpSReW7z7Bbb/A9OFjFhy8xZk6++3ukOWHoedKJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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