SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '737c65eeecf57905cb86bb43ceac8616608d481b29817628221653136150c3de' 
  AND token = '3rulWbrs9NduN0lbB1/Pg7KEpzK9uUSh7ItmBLtXqCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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