SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c78534923aad5dbebb4da468502d4f39dedba23bd678b84ff4814e07d62eb43' 
  AND token = '9kZIFtXUG5BbGJGptjq/4V9X/KGU3qj05sNpnLA6BDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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