SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10c5e7283ece8325e65dea2b0ab82263afa639427dfdd2bab20e85538d62c619' 
  AND token = 'gJoY1gS7PbOQNH5NcwxZr/eOwpI9gEAhGf9RuS7t9ao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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