SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91b962335c7794cb2aeb28f60076ff1b401b6382ebdb2f09471247266d71f5ba' 
  AND token = '545JcziYxRGFD/PT5b1jGiuUbyZnMbjz3FfYq/QMQWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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