SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2048971aeed4217751b7237140c6a684f66447158c9595a352533ae6b15bf208' 
  AND token = 'vu8+VvrdYMG8D3y9umsrRfxOUtMUrNZLoc0qW0sQzrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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