SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '899b14627226805a8a4e4d246b5d5b1361edb2bdedb63666fda84474d2a6edf0' 
  AND token = 'bROUh5pxh/sdX2JuBNliJa8mzDCMlyv9BtohQKZyhzw=' 
  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"
    }
  }
}