SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b0a0a8db16e98ac7ad68ab94736ceea829b74e1eb46f5e41a6e8ae24ed6c33c' 
  AND token = 'dUw8RuuEKSxcztqnpAnY01dTOrqRyEKNcFJ/woJRznk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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