SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78bcca06274d76e8f16aa05b052d34a16ec0a8b0090421b5501497fcf35f1890' 
  AND token = '8dK6b3QT0MxIJBP3iGHqyFg45IG7n6hODA/FmkaYJQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}