SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0b673c9595004da15e40bb0eeac2dda0d075d7a4e49899688d718d4d502115c3' 
  AND token = 'Nz+6dxHvLzMwQJlp0SHNxrDaYtOjZ0R6Xcy0ywhfNhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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