SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5c926409bb608a83507ad946d7eb2e58f5bde9ed453542be4f851247cd5981b' 
  AND token = 'Rxtw/QXs/h4LxecMoSjn80EnFdEzenXPtlLQuSILG1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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