SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7214032c408e9f7e3b11a6e2aa490d747f3a567c3cf98ee8326d3085ba13bbba' 
  AND token = '5BkCsj3LxYp3BG/x6ZzLgw3Vv3ggLiqoI1tar7C+PxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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