SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9373e11d36385f95b0968905d253a4f62263eb9eac8313796547786d3802a33a' 
  AND token = 'UprX7mXZuai4GwQQrCXxaMjiVbuXBixsqNhPzHqSVik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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