SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6d1a46692e01fdca8fd44ee2370bf86c96282fbdb2c558aff9852c255b5777a' 
  AND token = 'uKG+nBRoW8lYShtH+wY4N3JFRwV0TTKQOOPlv9QzweM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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