SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '987a4bfb0b81fca319cca66b896d3eb07acc13b4fc82cbe886a4a4352dc6d301' 
  AND token = 'KEIkQNX6eSIoRiI/IY/ZshSQvBt+9exmgAd6+GWuzFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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