SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e8aa8ee7ecfba5c765695928eb254ec1903f6f786f6430f967fdd136cbdf798' 
  AND token = 'cOqNkqhret9cFb0P0AqVOI3nyiZdSPEe68tyhTuCDSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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