SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '098f60184579823f70a5517f20bb75939c97e8e9c4dc5f5a4cdd8a6968cc11f8' 
  AND token = 'EkAj2pc9ZWAn0DBewYZV+BNXgAzixKbw1f1ssMMl1bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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