SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67fa2452a9d3559fa29ea565972166a391f43bc2ebc9b6436035a03db36c12c9' 
  AND token = 'XF44gNEcCxSxTpCBB30Z8UhJJGqIXcGh5ZgbeVoqH7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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