SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2296ed7e9ca9a3fd0a727fe1329863daaa2a28862c8c4595b51f55ff82a99309' 
  AND token = '4kKGEhWlyqOTaRjLB10LTQAWZqb3xzg0LSIsPu6Uj7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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