SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1381907cd503f7419f7bad2ec00eec8cc9cfca9ebe4f8302e4d955e661821c42' 
  AND token = 'K7Q/dXDk/HG9ZTYiB2mQ2NoJ6weBgl+SOyvWJjSjKaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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