SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '437eefd0b57108d5bc93b0cc42fe62cc6a49cb384e0cfd496b9702cea8dc6396' 
  AND token = 'KihJck3Ys0RT/gMbAORtTXNXtDC5vqtJmSN4pshlGh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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