SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e0393aadd0ef5568e0a52c546c5e35f957ec7f672a3c0caf1678d78e1205d03' 
  AND token = 'CSoL7geZg8JfEyo0kSqQELyKYFgIBIiw0Gc6LAihfaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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