SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '085837f15f2d043d7eb602a87e3a52bb01e4763954780d99e9c252b43a897c0a' 
  AND token = 'whp5SlFvJn2uAjBNTquOUqdTnipyIC+jzHW2DX/I7NE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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