SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78385ca6b599370dd9263818bb20f251b9ebb33f668c7eea46dc5afcf1d2dd99' 
  AND token = 'ZbXR+ptBwX0uqa7PKn/1Y0WpvoxRCbg+xvWC7YPOZxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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