SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2108be8b5a39a7e1145b647e2977e243135286d095f05efb26bc8e102acecd1' 
  AND token = '2TSmdDCa0pnJwPa164KdNj3nbE8rs7Aev5D2Uo/GfRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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