SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acb405165b40afcc76d7ab744ac28c86009d57907a71293f49e8710e99e91bef' 
  AND token = 'rKASf89w1y2DaqyrDzUpahkvFCJtDZ31IItZAtfwET4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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