SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fbf440e02fe0e08f4d3d7cd0fad69a6da83bdd43ce8d887b8b2ed4f693a14b3' 
  AND token = 'WMbQi8KSHI5ZziMXmdbLefIqF2YYKrOd9gryTpaGosc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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