SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56d13920351fb52bb539a68b9bca1256abd2aceb3e6e65abb8815143922afd19' 
  AND token = 'ivB71Iick8Kww7YTAUy/c+muZ2RGR/L+P/YYVLyHgqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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