SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1694095233ddba1a834f78193fbaec845d6afd62c19d262ee79bd2a728da621d' 
  AND token = 'rx5MdgBj8lLBZ3YjmPIzeKlne1HldobCXOpR+aFG+Zg=' 
  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"
    }
  }
}