SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '851850a08bfbd425eaa98c1db0102be0d60a360f8c14e102d8a74234e4e4c911' 
  AND token = 'E/SyLO1HxL4vfihVEjIgV8oJyVQsiVg5g556XhFrihc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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