SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29ea011e9d2f58304927c00bd86c061182548b588c677a7b38d46c59fa541056' 
  AND token = 'CTWfVGIcTVnWzgTs9aI/sZ4UyJ+0bMUKYxwIxNaCjyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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