SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e4e81b5bb7cf98199d55e0d5210e29a19af4812d5cc6283e232723ac320da45' 
  AND token = 'gKu+d4/YypV07MtgQzPgUcYHUm5hJB65Q14MYwaygsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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