SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd36d91f078c5e00b2f2fd2290727bc35c3b8ee61cdee6734016249ea19025485' 
  AND token = 'Hm9FiWR5ERqQkSl7KH2oH8XA4qFgNecHyhMyCByO1kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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