SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9c2d5b0aa74c78bc873e9d09c69f967ecac177f5af16613aed7f63d45174de0d' 
  AND token = '0ZnPc2ziUhUk1IZOj0W6RJmcYQUjLs8BeUHczSxmDvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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