SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '020890233bedc84388f938acd3c6d31bbb97d3cff0bf5703cb271b0723b249bb' 
  AND token = 'ExCL8liLgt2L4KUGQgRsL8HRjwc1V/IhO7IURCJtMjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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