SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26f6720db875062bf1be272e79f5e4fc9c47d0c340fb87b8e1367e20fc63a8ec' 
  AND token = 'JaL8lQPKGCTsZdrufxCHzc2waTfbqshsl94FYXEApZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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