SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b35e268598450320ad2668bf5f24198702c809d4deac7bf86b80ba94457daefe' 
  AND token = 'GdGRcCVA8D3lTNzhbiZCJG3XFsBFhcV95GnF6vXi2aA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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