SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94805c673addbaf519540cf937d73899b5b117de3e9c6e759250372d5f55565e' 
  AND token = 'fKQpcn4cdahyL/BQObzRIjLa6zOzWPygOZc/mkYRJnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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