SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58e5121f9129e2310388e616b72d03ccd2e2351da69deb6001b808e8f2a8a683' 
  AND token = '6wcVDh/hLh5SbdrfM/8qsVm/d6nUtAnr0FByq6efH2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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