SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c3d30dccd00db5e9e8b31d49d8875a4d56063b109852112927d2b3be278c617' 
  AND token = '01mrBZUsk0jOmJZgXuFaAk1da4QVS6kxO/V8IQSwRWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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