SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e532148f81232b97459e85d86c185df3b2496d3b402d14b6172d9ea2dbf6d07' 
  AND token = 'nMZblwZekfq8MP8KfxAlgbaM+GQLi4+vIHcljcBgl5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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