SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bbc7032bd8a5d751a8468cd1a993012b0576c9f54019ab28990905b438c0b61' 
  AND token = 'obmUCNfs2Ii/wADx0HUvLBe71BgWs6ul3LNOELCPiqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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