SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8323bf69c07a5539add36ba92f7ffe0bcd0549788609ff4609ff0d31f998e67' 
  AND token = '4qG+un3ZH9yt9Ukqmrju5WvFrH3FSf0+2gBLCnPPBFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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