SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d7790a0525a9f9da4e33fbbde034d476a93483b81311f60c0ffa6928ca6854c' 
  AND token = 'SgAS5XMk0ophhZiFY4oT2xpcJeeXb8oK5RWfW6QwMhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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