SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ba7da80de33e2c7b9b60f8203047e639fc3502a6248a235d254ead927065bfd3' 
  AND token = '+VVhzSSMG+PCn/si9NcwAXBJhwu6/wJlpU7j98QgvzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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