SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '286f3b3ac5e837b0f4d4ab63fb4ed2396fdf109788b00b50f8fec7c50fbcc085' 
  AND token = '5a1OXQmwqs5h5ey2G/HPBYYzRSCZR4JOm5vY+tQrFaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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