SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79f426d48d725d92aff8dc2bc02f5d125fcf05910a94fa2d12917e957d294acd' 
  AND token = 'rvjFXEuNuuUAOiLRO41j112XvHxC/QlSwat4iVjQSuQ=' 
  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"
    }
  }
}