SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b041aef04b58b436b7493f5a5056f2d535647f3631f2e09649066e14f785b46' 
  AND token = 'W/93kCBIjeGmwEwmhfJP5mhXzeCQ1YM8nsjtNoOoEFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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