SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b82024a250568c489021db097cf2d98a846d3c2c79cfa3362ce01bb08b61f3d0' 
  AND token = 'ZAHaaL46YLzFgEKQQVThdaVzLcfHPrqmsTEvQ7gPvkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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