SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c2fa3daa2923a8ce43a874664009d4a1014ffe091fce5ddbbf194554686b050' 
  AND token = 'QlX/4uyRzY/AbvJKGEKUJrK72uHVc4MxWB5iITMSnYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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