SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f416379167e3c63637b83e9f27c36e4861c17b632f07d36b5292c67e1b2c1712' 
  AND token = 'zy2VILKSJu/jMgSwBepGBxwrsfSD+5WzRpiSL7bw8yI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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