SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce29c91ab524aa7fae54602ee3a26b709c833a257984a9558b8f9bf992242ddf' 
  AND token = '40m0wcRfhJaFG2yDrrH75PdR0GEYBagFCm7KvygTwHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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