SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0be8877e9dbfd87ac211ebaa6faf588670f29966d5f6c8679c04040405f76a0b' 
  AND token = 'CbS/FSAWPRjbEJgk4i33ZyZxZUiND/dyeu6D9buX9BA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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