SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b43cc6dd961142d4c650326bb1a03b263927fe35317361660fe7385e2064bb4' 
  AND token = '0ui2Z7/SCYHtOeoS3geI9xbZrDKC/LkG2gQvwY4A9hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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