SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb6a12d04a3736530c74f5f018c79de9326943c63edff2d931a03529fac6c519' 
  AND token = 'JIaTM0tYlVccvzMHj5EaLoVZK47NGOccLl68KV+pJFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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