SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ba3487bc6f5f3e3a3b1d849306b3075e8c166570da7033c26b319f0dc7599a9' 
  AND token = 'pM6MvFMax8Sad5sax1vpON3s2aHlAimoH+beQjgBQ0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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