SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b73d14ed0342baabfdccd567bdfa28c39d9978d2eaf6aa6a9327df371f4e2fa7' 
  AND token = '1NRtt6mQKjZI3h5U5PNjJTAeyDDwPoi3xvsxQgrGJVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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