SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d486039fc05998f10e459f305a74cc94ac9aeb23c195ee4bdfc9a9e64448214' 
  AND token = '7YhW5srPvlAAII38gWmu3haB8giwAYoOFI2Vp7NupcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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