SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f16fdecc8b5b5d1a48b1251bf2b3a30c848faa681762a9809c7e9f9a4b6191e9' 
  AND token = 'MAkWeKpxUXz4muGL3B+PtlGp5WvuttgQ5IFzBHsZmL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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