SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83140fbaf780fb5c1a09f711e185a03a9367a2a0989a7166ec2f33866a4eca8d' 
  AND token = 'HsNfK94jDu8zapCELvCHyWxdwy0oIjr1sfOjnp5h+KI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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