SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e21c825bf883a7b1569bee39979b5995f3a34f24aaa5f628a73c740b7f73d41e' 
  AND token = 'zXbVLppYaiPAIlroPCLmqHi5vGEFS4/ZKYWvLBfTJwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}