SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb406b6813389ba64a532fc89826f167c77e4efb102721585280d76f82b56a81' 
  AND token = 'rOT5EruXyUG+vvqLkAgrlhRw8FnRYKOQA7eLCDlag3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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