SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5be7c4b28c17997384892590cc7dc773efb117e6ec904f0424da6407391ccfcd' 
  AND token = 'G6jjqQThtftOevOqQ+8ArzPTDl6Z0tI7rShazXQ8kIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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