SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '109890e49656d326d72bb9e14c75b96f96c8a178f9870fa62320cf5154d259fc' 
  AND token = '8tELYV1zt2OoE7mptnhL3/wlFgB+CvZU8mNgq4ITRwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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