SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a52aa872e6dd0e4fd1d0784d83428efec9826d26aefe02de7ce83b7302f4630' 
  AND token = 'WZOlzLcfs8KIC7MvxUHsfZDLV25OnRGqdPatOdCKtz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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