SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '047e70edfb78ec2b627995322e7fc015ef017c7132a9feff190c988c9fb558af' 
  AND token = '/Nabwdna61FgM4fJSPdftyLUny5R94JvxnVVr6p56Jo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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