SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5bcc20f6da78edda8df46ce619ff6f25d9406b543f6041fbdf91694a8cde480' 
  AND token = '3AUNLn+2hp3umn3quC4deqI+xkUaLDmqHSZewRkaGbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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