SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c06c9f78b4f76b6d6bad476c65c61ae733011ef850cb9e446e16d5fe46a6efb' 
  AND token = '6EYR9eA4OLaVTkRmKgk1J2qDwTpE/quJEdvIqIo4GYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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