SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '914a46b92b976daf06d18d0a0c1f0d685f7ddd617bb4b7c42f634dc896850b05' 
  AND token = 'QgL/LxTdvjcssTS/CWw7xt5tR8s/ZvddKNMwsB/N0Ig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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