SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ad830f31fb5bc783039500d3e6495d2821cb3cc675cfc9453c0ed7d4a99dd11' 
  AND token = 'R9+BucBTvPVkapX2BuwQmd6XyQy0uzyjquIJkKe27M0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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